Many buildings are required by code to have fire suppression sprinkler systems. Further, residential structures are increasingly being provided with fire suppression systems. CPVC piping systems are ideally suited for fire sprinkler system applications because of their resistance to corrosion, the lightness of material, ease of installation, and other desirable properties. Additionally, many buildings and offshore applications include drainage, waste, and ventilation (DWV) systems, which can be utilized in connection with transporting/treating possibly toxic chemicals. CPVC piping systems, due at least in part to resistivity to fire and smoke are well suited for these applications.
Under current standards, in-line coupling of abutting CPVC pipe sections is accomplished by use of solvent cement techniques to form a permanent bond therebetween. Such techniques require sufficient time for the solvent cement to cure. Furthermore, at times it may become necessary to make modifications or repairs to existing CPVC piping systems. The use of solvent cement demands that the modification to the pipe network be accomplished in a generally dry environment.
In use, many piping systems, including fire systems and DWV systems, may be under continuous water pressure or varying water pressure. In prior CPVC piping systems, for a system modification or repair, the pipe section must be removed from service and drained. The new CPVC pipe sections must be connected into the system adhered by solvent cement which requires an applicable cure time. Thereafter, the system is brought back online and tested. During this process, which may extend over 24 hours or longer, at least a portion of the piping system is out of service, requiring, for instance, an alternate fire watch or a DWV system to be temporarily unavailable. Use of the solvent cement creates an irreversible pipe connection. Thus, misalignment or other adverse conditions cannot be readily corrected. Further, some piping systems, such as piping used in some food preparation systems, require frequent disassembly for cleaning.
One solution to this problem is to utilize a mechanical coupling that sealingly engages annular grooves rolled or cut into the two pipes to fasten them together. This avoids the use of solvent cement.
However, CPVC pipes are more flexible than metal pipes and therefore need more support. The additional support adds to the installation time and also the material costs due to the additional material of the entire system. Therefore, it is often desirable to use multilayered composite pipes that comprise a metal layer sandwiched between inner and outer layers of CPVC to provide the necessary support while still providing many of the advantages of CPVC pipes.
Yet, the method of cutting or rolling grooves into CPVC pipes is not desirable for use on the above-mentioned multilayered composite pipes. In rolled grooving, material is pressed inwardly to form a circumferential depression on the outer surface. The method of cutting a groove involves having pipe wall material removed by a blade or other cutting implement. Either cutting or rolling a groove in these multilayer composite pipes would break or delaminate the outer layer and possibly the inner layer as well.
Thus, there exists a need to provide a method to join multilayered composite pipes which eliminates the down time associated with prior joining processes yet will maintain the integrity of the pipe.
There also exists a need in the art for a fluid handling assembly comprising multilayer composite pipes and couplings that couple the pipes together without the use of solvent cement to couple the couplings together.
There further exists a need in the art for cut-in fittings and procedures that significantly reduce downtime of the sprinkler system, while still providing a system that meets stringent fire protection standards.
If mechanical couplings and fittings are to be used with CPVC pipe systems, such items should be utilized in ways that accommodate the properties of the CPVC piping. Compression and support requirements of the CPVC material should also be met. Thus, there exists a need for mechanical fixtures that are compatible with the properties of the CPVC material in the pipes.
There also exists a need to connect non-composite plastic pipe to composite plastic pipe or to another length or non-composite plastic pipe with a mechanical coupling device, without the requirement of forming a groove in the plastic pipe.
Further, certain fire testing standards have been developed that are specific to plastic piping systems. Incorporation of mechanical fittings and adapters into such systems requires that the hybrid system meet certain performance standards. Thus, there exists a need for a plastic/mechanical system to perform in accordance with accepted fire standards.
There also exists a need to connect a plastic pipe, either composite or non-composite with a metal pipe, without the requirement of forming a groove in the plastic pipe.
The above described needs can be accomplished by using a coupling bushing as described herein.